This site was last updated on July, 2010
Quartz Crystal Habits within Herkimer Diamond Deposits
Definitions and Scope:
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Larger photos of the thumbnails presented on the main "Crystal Form" page. Included is identification information and the source link is embedded there (just click). In some cases additional information and comments are provided for each photo.
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Twins and Odd Shaped Crystal Forms - Are these all Herkimer Diamonds?
Below is a picture showing a series of quartz domes that were surrounded by hydrocarbon.
From Fonda, NY (DA - 2007). This is not a typical shape for Herkimer quartz. And probably no one would call this a "Herkimer diamond". Yet the quartz is the precursor to forming the classic "Herkimer diamond". Photo Dr. D. 2009
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Web page author - W. David Hoisington, Ph.D.
Above (left) is a Jeff Scovil photo, taken 1995 and donated 2009. It is 3.7 cm long and from the Rod Robinson collection, labeled "from Herkimer, NY". This is obviously a unique crystal shape with the termination bent like the nose of a hawk.
A second crystal (upper right) is from the TCR location and shows a similar "hawk nose" termination. It is also smoky at the top. The crystal is from the mine owners collection and is 2 cm long, Photo Dr. D., 2010
These two photos are of a crystal from TCR (Photo Dr. D., crystal 3 cm long). Note the elongated prismatic habit like the "hawk nose" crystal. In addition there is a single termination face that is enlarged (see the black arrows) on both terminations of this crystal. This crystal is double terminated and clear, but should it be called a "HerkimerDiamond"?
Or should it be called by its habit name?
On the right - snother crystal from TCR (photo Dr. D., crystal is 4 cm point to point). At the arrow is a single termination, but at the other end (top) are multiple terminations in parallel arrangement (called parallel growth). Note also the step pattern and that the faces on the steps are all parallel to each other (light reflection used to highlight this feature).
Parallel growth habit is also common to HBQ.
This dome habit for quartz in the Herkimer District is not uncommon, but it seldom makes it into collections. Most is likely resting under piles of waste rock at the mines. The formation of these domes might be linked to the same processes that made the quartz spheres.
Above (left) is a smoky colored crystal, 5 cm tip to tip, from TCR (photo Dr. D. 2009). The TCR deposit has a higher frequency of these special shaped crystals that have very small m (prism) faces. The m face is labeled on the above diagram with the Dauphine crystals to illustrate the difference. The smoky color found in Herkimer diamonds is not rare, but it is not as common as the clear or white. To the right is a photo of a small crystal, more common to TCR, with the m-face almost missing. This is called the "Cumberland Habit" named after a location in England.
There is some question as to whether these should be called "Herkimer diamonds" or more appropriately give respect to their unique form and maintain the Cumberland habit term.
<- m face
The Cumberland habit in the Herkimer diamond mining district - Are these to be called "Herkimer diamonds"?
<- m face
The TCR deposit also has some other unusual shaped crystals as well as some excellent skeletal and hopper crystals (see the skeletal page).
The TCR deposit page has an excellent photo of Cumberland habit in matrix where the m face is absent on one side.
Parallel Growth Habit
To read a discussion on why some quartz is smoky go to the FAQ page
What crystal habit is this?
This "hawk nose" termination, when it occurs as a double termination, shows the tips pointing in opposite directions. This is shown in the 1.7 cm crystal to the right from HBQ (Frank's Collection) - photo Dr. D. 2010
Are these to be called "Herkimer Diamonds"?
Click to the sphere page
Below is a large curved surface on a crystal that was packed in hydrocarbon. Note the attempt to form a termination (bottom of photo). Fonda, NY (DA - 2008) specimen donated by "Deputy Mike". Photo Dr.D. Is this a Herkimer diamond?